The present invention is directed to the fields of roadside assistance, electric vehicle charging, modular energy storage systems, and related fields.
In recent years, the popularity and affordability of electric vehicles (EVs) such as battery-powered EVs, hybrid gasoline-electric EVs (or HEVs), and other vehicles having motors and engines powered by electrical energy has grown dramatically. As these vehicles gain more market penetration and presence, there will be a need for increased on-the-road-services for EVs, such as providing a “boost charge” to the EV, similar to how service vehicles provide a motorist with a gallon of gasoline to get them to the next fueling station today. One of the challenges in providing these services will be the numerous differing standards used in the batteries of electric vehicles that are coming to market, since their various battery chemistries, capacities, and dimensions make the range and charging requirements of each vehicle quite different. For example, small EVs will only need a small amount of energy to allow them to travel safely to a dedicated service or charging area, but large electric vehicles will require a relatively large charge of energy to reach a service area due to their larger energy consumption rates.
Furthermore, vehicles involved in roadside assistance will be compelled to recharge or refill their boost charging equipment, resulting in losses due to inefficiency and downtime. Recharging energy storage takes time, so although batteries and chargers are improving in their ability to accomplish this in less time, this process will always set a lower limit on the time interval between uses of a battery-based EV-recharging rescue vehicle with built-in energy storage.
Removable batteries are common in electrical equipment, and even some EVs have removable batteries to provide motive power to the vehicle. One of the challenges in using removable batteries is the danger to operators that arises from the high powered connectors for the batteries. Some inventors use plastic shrouds or robotic battery manipulation for personal protection from exposed electrodes or simply use no protection at all, leaving the operator and equipment at risk. These systems can make it dangerous to use and store a battery-powered EV charging system. Some systems with removable batteries insert a “dead” power supply or other electronic device into a “live” backplane. This configuration is not ideal since it doesn't allow for the de-activation of a “live” battery tray during handling without some human intervention, like opening a switch or removing a fuse, and since humans can forget to take these safety measures there is a greater risk of personal injury in these systems. Some systems envision large battery swap-out stations for EV batteries instead of recharging them while in the EV. The EV batteries swapped out therein can be approximately 25 kWh in capacity, can weigh 500 pounds or more, and require robotic devices to remove and install them. They also typically have a multi-person crew. This is expensive, and the proprietary nature of the swappable battery designs leads to difficulties in compatibility of vehicle systems and swapping stations.
Another challenge in this field relates to how to minimize the size and weight of the battery and the balance of the onboard systems of the rescue vehicle's onboard electrical generation system. This optimization makes it more efficient to recharge an energy store for repeated uses over relatively short time intervals. Sizing an onboard battery pack for the most demanding, worst-case stranded vehicle is impractical and expensive. Some assistance solutions use permanently installed batteries which occupy the battery housing at all times and can only be removed with labor-intensive and time-consuming effort. Permanently installed batteries render the host vehicle completely dependent on said batteries both in charging time and charging frequency, since it takes time for a charging event to complete, and the batteries require a resting period between recharges to prevent overheating. Large batteries are also expensive and heavy so a generator system having them is burdensome and oversized when charging events are relatively infrequent when compared to other activities of a rescue vehicle.
Near-term future deployments of rescue vehicles are likely to initially require minimal electrical storage capability due to the limited market penetration of EVs. However with increased EV market penetration it will become increasingly important to gracefully grow rescue vehicle electrical capability to meet customer demand without needlessly expending large capital outlays for battery systems before such larger systems are required by the marketplace. Even if charging systems are designed with removable batteries and quick disconnects, swapping them out between one location and another can raise challenges for operators. Operators may need to rapidly respond to an emergency situation while on heavy trafficked road, and there are many potential safety-related issues associated with moving high-energy battery modules.